Full opinion text
LUCERO, Circuit Judge. This case involves petitions for review of actions by the United States Environmental Protection Agency (“EPA”) under the Safe Drinking Water Act (“SDWA”), 42 U.S.C. §§ 300f to 300j-26. Petitioners Hydro Resources, Inc. (“HRI”) and New Mexico Environment Department (“NMED”) challenge EPA’s decision to implement the direct federal underground injection control (“UIC”) program on certain New Mexico lands, the jurisdictional status of which EPA considers disputed. Petitioner NMED challenges an additional EPA decision to implement the direct federal UIC program on adjoining lands that EPA considers Indian country under 40 C.F.R. § 144.3 and 18 U.S.C. § 1151. These petitions require us to consider several important questions, including the level of procedural formality required for EPA decisions regarding federal Indian country jurisdiction under the SDWA; the effect of state adjudications against a tribe on EPA’s authority to assess whether lands are Indian country; and the Indian country status of certain federal trust lands in the Eastern Navajo Agency. We exercise jurisdiction under 42 U.S.C. § 300j-7(a)(2), dismissing in part and remanding in part. I The historical and procedural background is complex and implicates issues of administrative and environmental law as well as federal Indian law. To elucidate the issues involved, we briefly relate the history of the lands in question and the procedural history of their regulation under the SDWA. A. Background: Sections 8 and 17 and the Eastern Navajo Agency HRI, a non-Indian corporation, proposes to operate a uranium mine in McKinley County, New Mexico. This mine site — the “Churchrock mine” site — is located in an area of northwestern New Mexico often known as the “checkerboard” because of its pattern of mixed Indian and non-Indian land title, originally stemming from railroad land grants. The lands at issue consist of two parcels. The first comprises approximately 160 acres located in the southeast portion of Section 8, Township 16N, Range 16W, owned by HRI in fee simple and hereinafter referred to as the Section 8 property. The United States owns the remainder of Section 8 in fee simple; the status of that land is not at issue here. The second parcel is in Section 17, Township 16N, Range 16W, south of and contiguous to the Section 8 property. Section 17 is a split estate. The surface is owned by the United States in trust for the Navajo Nation. HRI holds the mineral rights, as well as certain surface use rights under a 1929 reservation and a 1959 Surface Owner’s Agreement between the Nation and Santa Fe Pacific Railroad Company, a predecessor in interest to HRI. This agreement allows HRI to use the surface of Section 17 for mining purposes. This petition for review concerns approximately 200 acres in the northwest quadrant of Section 17 — hereinafter referred to as the Section 17 property. These lands are located in the “checkerboard” area of the Eastern Navajo Agency, within the borders of the State of New Mexico, in an area often referred to as the “EO 709/744 area” because of its establishment as an Indian reservation under two executive orders bearing those numbers. In Pittsburg & Midway Coal Co. v. Yazzie, 909 F.2d 1387, 1419-20 (10th Cir.1990) (hereinafter Yazzie), a case involving Navajo efforts to tax a coal mine in northwestern New Mexico, we held that the reservation status of the EO 709/744 area was terminated by executive and Congressional action. We noted that not long after Executive Orders 709 and 744 added some 1.9 million acres of land in northwestern New Mexico to the Navajo Reservation in 1907, Presidents Roosevelt and Taft issued two additional executive orders, EO 1000 in 1908 and EO 1284 in 1911, which restored unalloted lands in the EO 709/744 area to the public domain. See id. at 1391-92. Concluding that the language of restoring lands to the public domain sufficed to terminate the EO 709/744 area as a reservation, see id. at 1419, we declined to declare the entire EO 709/744 area to be a de facto reservation in the face of evidence of Congressional intent to disestablish that area, see id. at 1420. We nevertheless recognized the predominantly Navajo demographic character of the area, see id. at 1419, and the complicated jurisdictional questions created by the “checkerboard” nature of land titles in the area, id. at 1421, and remanded the case to the district court to determine “to what extent the surface rights of the South McKinley Mine are held by the Navajo Tribe or by Navajo allottees.” Id. at 1422. Some of the jurisdictional questions that Yazzie left open were revisited in Pittsburg & Midway Coal Co. v. Watchman, 52 F.3d 1531 (10th Cir.1995) (hereinafter Watchman), which reversed the district court’s finding on remand that the South McKinley Mine is not Indian country under a “dependent Indian community” analysis. See id. at 1542-45. Relying on Supreme Court and circuit precedent recognizing dependent Indian communities both geographically very large and very small, we held that the district court erred in restricting the “community of reference” of its analysis to the mine site alone. See id. at 1543-45. Watchman also stated a four-part test for determining whether a given community of reference constitutes a dependent Indian community under 18 U.S.C. § 1151(b). See id. at 1545. B. Statutory Framework under the SDWA The SDWA is an environmental statute establishing overall minimum drinking water protection standards for the nation, and providing, in many instances, for delegation of specific regulation and enforcement to states and Indian tribes. The statute directs EPA to establish minimum requirements for control of underground injection processes in order to protect sources of drinking water. See 42 U.S.C. § 300h. 42 U.S.C. § 300h-1 provides for state primary enforcement of UIC programs (“primacy”) upon a showing by that state that its program meets the requirements of the SDWA. For states without programs, or whose programs have been disapproved, EPA is required to prescribe federal UIC requirements. See 42 U.S.C. § 300h-1(c). In 1986, Congress added 42 U.S.C. § 300h-1(e), providing for primary UIC program enforcement responsibility by an Indian Tribe under certain circumstances. 42 U.S.C. § 300h-1(e) additionally provides that until a Tribe assumes primary responsibility, the “currently applicable underground injection control program shall continue to apply,” and if such program does not exist, EPA shall prescribe one. 1. UIC Programs: State, Federal, and Tribal Two UIC programs are at issue in this case. One is New Mexico’s program, the other EPA’s program for Indian lands. EPA approved New Mexico’s program for “Class III” wells, used for in situ leach uranium mining, effective August 10, 1983. See 40 C.F.R. § 147.1601. The approval of New Mexico’s program specifically extended to “[certain categories of] injection wells in the State of New Mexico, except for those on Indian lands.” Id. Effective November 25, 1988, EPA approved an EPA-administered UIC program for “Indian lands in New Mexico.” 40 C.F.R. § 147.1603. After Congress in 1986 authorized EPA to treat Indian tribes as states for SDWA purposes, see 42 U.S.C. § 300h-1(e), the agency approved the Navajo Nation, in 1994, for Treatment as a State (“TAS”) with respect to “all lands located within the exterior boundaries of the Navajo Reservation ... all satellite reservations ... and the following lands located outside the boundaries of the formal Navajo Reservation within the Eastern Navajo Agency: all Navajo tribal trust lands, all Navajo allotments, and all tribal fee lands and federal lands previously determined to be part of ‘Indian country.’ ” (VI R. Tab 112 at 1.) EPA did not approve the Navajo Nation’s TAS application with respect to private fee lands and state trust lands within the Eastern Navajo Agency, stating that the Navajo Nation had “not demonstrated the requisite jurisdiction.” Id. The Navajo Nation has not yet assumed primacy in SDWA enforcement for those lands for which its TAS application was approved. In the preamble to its final rule promulgating federally administered UIC programs for, inter aha, Navajo Indian lands, EPA addressed comments regarding the agency’s treatment of the jurisdictional boundaries of Indian lands. See 53 Fed. Reg. 43096, 43097 (Oct. 25, 1988). The preamble states in relevant part: [T]he definition of Indian lands adopted for the UIC program is set forth in 40 CFR 144.3. Whatever definition is chosen, there will be disagreements about whether particular lands fall within the definition. An Indian tribe would probably object to a State exercising jurisdiction over lands it perceives as Indian lands, and a State would object to an Indian tribe exercising authority over lands which it believes to be non-Indian lands. Thus, disputes could prevent both the State and the Indian tribe from exercising primary enforcement responsibility for a UIC program. In order to ensure regulation of injection wells and minimize any disruption, pending the resolution of jurisdictional disputes, EPA will implement the Federal UIC program for disputed lands. Id. To avoid undue delay in implementation of the UIC program, EPA set forth the following strategy for implementing the UIC program on disputed lands: As described above, EPA will assume that lands described by the definition in 40 CFR 144.3 are Indian lands and will begin implementation of the UIC program on them. If disputed territory is later adjudged to be non-Indian lands, it will be deleted from the EPA Direct Implementation Indian land program and added either to the EPA (non-Indian land) DI program for that state or to the State program, as appropriate. Id. 2. Aquifer Exemptions As a general rule, the SDWA prohibits contamination of an underground source of drinking water, defined broadly at 40 C.F.R. § 144.3. Because certain aquifers within that definition will never be used as sources of drinking water, however, EPA adopted criteria for exempting certain aquifers from SDWA requirements. See 40 C.F.R. § 146.4; see generally Western Nebraska Resources Council v. EPA, 793 F.2d 194, 196 (8th Cir.1986) (hereinafter WNRC) (describing aquifer exemption process). 40 C.F.R. § 144.7(b)(3) provides that “[subsequent to program approval or promulgation, the Director may, after notice and opportunity for a public hearing, identify additional exempted aquifers.... Any disapproval by the Administrator shall state the reasons and shall constitute final Agency action for purposes of judicial review.” EPA regulations specify that the identification of an aquifer as exempt, subsequent to a grant of primacy to a state or tribe, is a revision to that state or tribe’s UIC program under 40 C.F.R. § 145.32. See 40 C.F.R. § 144.7(b)(4). Program revisions that EPA deems substantial must be carried out in accordance with the rule-making process set forth in 40 C.F.R. § 145.32(b). See WNRC, 793 F.2d at 199 (concluding that approval of 6.7 acre aquifer exemption is “nonsubstantial program revision” that need not be accomplished through formal rulemaking). The SDWA itself provides for a public hearing regarding promulgation of any rule approving, disapproving, or approving in part a state’s UIC program under 42 U.S.C. § 300h-1(b)(2) or (3). See 42 U.S.C. § 300h-1(b)(4). Agency regulations also provide procedures for revision of state programs, see 40 C.F.R. § 145.32, and withdrawal of state programs, see 40 C.F.R. § 145.34. C. Procedural History In 1989, NMED approved a “discharge plan” (DP-558) for underground injection by HRI on property located within Section 8, and applied for an aquifer exemption for the underlying aquifer. On June 21, 1989, EPA approved New Mexico’s request for an aquifer exemption for HRI’s Section 8 mine site. In April 1992, HRI requested extension of its permit to Section 17, and NMED applied for an additional aquifer exemption for the Section 17 property. Following a hearing and comment period, EPA issued a letter from the Director of the Water Management Division of EPA Region 6 to the Secretary of NMED, declining to approve the Section 17 aquifer exemption on the ground that Section 17 is Indian land under 40 C.F.R. § 144.3. New Mexico, however, continued to process HRI’s DP-558 permit. The Navajo Nation moved to dismiss the state'permit proceeding for lack of jurisdiction on the ground that Section 17 is Indian country. In mid-1994, a NMED hearing officer denied the Navajo Nation’s motions and issued a proposed order, subsequently adopted by the Secretary of NMED, ruling that New Mexico had authority to regulate the Section 17 property and that Section 17 was not Indian country. The Navajo Nation appealed NMED’s decision to the New Mexico Water Quality Control Commission (“WQCC”). The WQCC hearing officer dismissed the appeal as untimely. Another state proceeding also involved the lands in question here. This proceeding is referred to as the “G-190 application,” a water rights proceeding before the New Mexico State Engineer. In the G-190 application proceeding, HRI’s predecessor-in-interest, the United Nuclear Corporation (“UNC”), sought a transfer of water rights pertaining to the Churchrock mine site. The Navajo Nation opposed the water rights application on its merits, and also objected on the ground that the State Engineer lacked jurisdiction over Sections 8 and 17 as Indian country. The State Engineer adopted a hearing officer’s report finding New Mexico had jurisdiction, but denying UNC’s transfer application on its merits. UNC sought review in state court, and the Navajo Nation moved to dismiss for lack of jurisdiction, based again on the Indian country issue. The state district court affirmed the State Engineer’s judgment, finding insufficient water rights on the merits. Its opinion also stated, without analysis, that “[t]he mining areas in Section[s] 8 and 17 are not within the boundaries of the Navajo Nation nor are they Indian country; therefore, the water rights within them are subject to state law.” (Ill R. Tab 67 at 1.) The Navajo Nation appealed the jurisdictional issue; UNC initially cross-appealed the ruling on the merits, then moved to dismiss its cross-appeal. The New Mexico Court of Appeals dismissed UNC’s cross-appeal, and in February 1996, dismissed the Navajo Nation’s appeal as moot. In August 1995, subsequent to the 1994 NMED decision on the Section 17 amendment to DP-558, NMED again requested from EPA an extension of the Section 8 aquifer exemption to Section 17. EPA again, in a letter from Region 6 dated August 24, 1995, rejected the state aquifer exemption and stated that HRI must obtain a federal UIC permit prior to obtaining an aquifer exemption. This letter instructed HRI and NMED that HRI should submit applications to EPA region 9 for an aquifer exemption under the federal UIC program. Following Region 6’s August 24, 1995, TAD disapproval, NMED engaged in a lengthy process with EPA Region 9 and the Navajo Nation to resolve the jurisdictional dispute through “joint permitting” of Section 17. During 1995 and 1996, representatives from EPA, NMED, and the Navajo Nation met and exchanged correspondence regarding a hybrid joint permitting scheme. These communications culminated in the EPA letter giving rise to the current dispute. This July 14,1997, letter, sent to NMED Secretary Mark E. Widler and copied to HRI, stated EPA’s position requiring federal permitting for both Section 17 and Section 8. Specifically, it notes: “EPA believes that Section 17 clearly is Indian country,” but also “treatfs] the status of Section 17 as in dispute” — requiring federal permitting but not requiring NMED to concede jurisdiction. (I R. Tab 48 at 2.) Further, based on EPA’s determination that “the Navajo Nation has presented substantial arguments to support its claim that Section 8 is within Indian country,” the letter indicates that EPA would treat Section 8 as in dispute under the dispute rule of the Indian lands UIC rule preamble. Id. With respect to Section 8, the letter provides that “EPA has not taken a final position on the Indian country status of Section 8, only that the status is in dispute.” Id. The letter and a legal analysis contained in an accompanying memorandum rejected the argument that the state proceedings foreclosed EPA from acknowledging a jurisdictional dispute over the lands in question. II As an initial matter, we must ascertain whether we have jurisdiction to review these EPA actions. 42 U.S.C. § 300j-7(a)(2) provides for review of any action by the Administrator of EPA under the SDWA (other than actions pertaining to the establishment of national primary drinking water standards) “in the circuit in which petitioner resides or transacts business which is directly affected by the action.” Section 300j-7(a) further provides that [a]ny such petition shall be filed within the 45-day period beginning on the date of the promulgation of the regulation or any other final Agency action with respect to which review is sought ... and may be filed after the expiration of such 45-day period if the petition is based solely on grounds arising after the expiration of such period. 42 U.S.C. § 300j-7(a). This 45-day period is jurisdictional, reflecting “a deliberate congressional choice to impose statutory finality on agency [action], a choice we may not second-guess.” WNRC, 793 F.2d at 198 (quoting Eagle-Picher Indus., Inc. v. EPA, 759 F.2d 905, 911 (D.C.Cir.1985)); see also Mesa Airlines v. United States, 951 F.2d 1186, 1187 (10th Cir.1991) (stating that statutory time limit for review of administrative agency action is “jurisdictional and not discretionary”). A. Section 8 With respect to Section 8, the petition for review is timely. EPA announced its decision to treat the Section 8 lands as disputed Indian country and implement the direct federal UIC program in a letter dated July 14, 1997, and the petitions for review were filed August 27, 1997. We must additionally determine, however, whether petitioners’ challenge with respect to EPA’s actions regarding Section 8 is ripe for purposes of judicial review. See Mobil Exploration & Producing U.S., Inc. v. Department of Interior, 180 F.3d 1192, 1197-99 (10th Cir.1999). Before we can review an agency decision, we must assess “the fitness of the issues for judicial decision and the hardship to the parties of withholding court consideration.” Ash Creek Mining Co. v. Lujan, 934 F.2d 240, 243 (10th Cir.1991) (quoting Abbott Labs. v. Gardner, 387 U.S. 136, 149, 87 S.Ct. 1507, 18 L.Ed.2d 681 (1967)). In making this determination, we look to four factors: (1) whether the issues in the case are purely legal; (2) whether the agency action involved is “final agency action” within the meaning of the Administrative Procedure Act, 5 U.S.C. § 704; (3) whether the action has or will have a direct and immediate impact upon the plaintiff and (4) whether the resolution of the issues will promote effective enforcement and administration by the agency. Ash Creek Mining Co., 934 F.2d at 243 (citations omitted). As for the first factor, the questions of agency compliance with the relevant statutes and regulations and of jurisdiction under federal Indian law present purely legal issues. The second question is whether agency action is final within the meaning of the APA. The SDWA specifically provides for review of “any other final action of the Administrator,” 42 U.S.C. § 300j-7(a)(2); the pertinent question is whether EPA’s July 1997 letter represents such a final action. The Supreme Court has stated that: As a general matter, two conditions must be satisfied for agency action to be “final”: First, the action must mark the “consummation” of the agency’s decisionmaking process, Chicago & Southern Air Lines, Inc. v. Waterman SS Corp., 333 U.S. 103, 113, 68 S.Ct. 431, 92 L.Ed. 568 (1948) — it must not be of a merely tentative or interlocutory nature. And second, the action must be one by which “rights or obligations have been determined,” or from which “legal consequences will flow,” Port of Boston Marine Terminal Assn. v. Rederiaktiebola-get Transatlantic, 400 U.S. 62, 71, 91 S.Ct. 203, 27 L.Ed.2d 203 (1970). Bennett v. Spear, 520 U.S. 154, 177-78, 117 S.Ct. 1154, 137 L.Ed.2d 281 (1997) (parallel citations omitted). The second Bennett condition is met here: Definite legal consequences flow from EPA’s designation of Section 8 as disputed Indian lands for SDWA purposes, namely the requirement that HRI apply for a permit under the federal UIC program to proceed with underground injection. What the Navajo Nation contests is whether the action marks the consummation of the decision-making process. See Mobil Exploration, 180 F.3d at 1197-99 (holding that “tentative or interlocutory action” does not represent “the consummation of the agency’s decisionmaking process” and thus is not final agency action for APA purposes). In the July 14, 1997 letter, EPA Regional Administrator Felicia Marcus states “I want to emphasize, though, that EPA has not taken a final position on the Indian country status of Section 8, only that the status is in dispute.” (I R. Tab 48 at 2.) It is our view that EPA’s designation of Section 8 as disputed Indian country is a final action — so far as it goes. The determination that a dispute exists represents the consummation of one decision-making process, and necessarily alters legal relationships. See Ash Creek Mining Co., 934 F.2d at 243. Judicial evaluation of whether that determination was proper under the relevant laws and regulations will undoubtedly be of benefit to all the parties, allowing them to proceed on the proper course within the framework of the SDWA regulatory relationship. The question of the propriety of EPA’s invocation of its dispute rule, however, is a distinct one from the underlying legal matter of the Indian country status of Section 8. EPA’s July 14, 1997, letter, as well as government counsel’s assertions at oral argument, indicates that the agency has not taken a final position on the underlying jurisdictional question; the agency requests instead the opportunity to develop a further administrative record in light of Venetie, 522 U.S. 520, 118 S.Ct. 948, 140 L.Ed.2d 30. Thus, although we will address the question of whether the agency properly designated Section 8 as “in dispute” for purposes of SDWA regulation, we conclude that if such a dispute does exist, its merits are not ripe for further judicial review at this juncture. See Mobil Exploration, 180 F.3d at 1197-99. As for the additional Abbott Laboratories ripeness requirements, the action in this case does have a direct and immediate impact on petitioner HRI&emdash;HRI must now obtain a permit from EPA prior to commencing underground injection on Section 8. It is less apparent whether the Section 8 action has an immediate impact on petitioner NMED. EPA’s July 14, 1997, letter refraining from taking a final position on the Section 8 jurisdictional issue does not appear to foreclose entirely some sort of joint or dual permitting scheme. Because HRI has not sought the federal permit, we are not faced with a situation in which HRI would proceed with underground injection under a federal permit that does not satisfy the requirements of New Mexico’s UIC program. However, given that at least HRI is impacted by the decision, we need not delve further into the degree to which it impacts NMED. Resolution of these issues would certainly promote effective enforcement and administration by the agency, and resolution of the jurisdictional status of these lands will facilitate regulation by the appropriate authorities of underground injection activity. See Ash Creek Mining Co., 934 F.2d at 243. Therefore, we conclude that under the APA, EPA’s decision to treat Section 8 as disputed Indian country and impose federal UIC requirements is final and ripe for judicial review. The underlying question of the final Indian country status of Section 8, however, is not yet ripe for review because EPA has not completed its decision-making process with respect to that issue. See Bennett, 520 U.S. at, 177-78, 117 S.Ct. 1154. B. Section 17 As for Section 17, respondents EPA and Navajo Nation argue that NMED’s petition for review is untimely under 42 U.S.C. § 300j-7(a). We disagree. EPA’s decision, contained in its letter of July 14,1997, to treat the jurisdictional status of Section 17 as “in dispute,” constitutes a revisitation of EPA’s prior decision, thereby reopening the decision for review. EPA’s initial determination that Section 17 is Indian country was made in EPA Region 6’s denial of NMED’s request for a Section 17 aquifer exemption on November 23, 1993. According to the explicit terms of 40 C.F.R. § 144.7(b)(3), this disapproval was a reviewable final agency action for purposes of 42 U.S.C. § 300j-7(a)(2). No petition for review was filed within 45 days of that aquifer exemption disapproval. Therefore, the instant petition for review can be timely only if it is either “based solely on grounds arising after the expiration of such period,” 42 U.S.C. § 300j-7(a), or else within the 45-day period of a later and distinct final agency action, including, under certain circumstances, one reconsidering and reaffirming the initial decision. See, e.g., ICC v. Brotherhood of Locomotive Eng’rs, 482 U.S. 270, 278, 107 S.Ct. 2360, 96 L.Ed.2d 222 (1987). Petitioners cite to EPA Region 9’s July 1997 letter as a separate and reviewable final action, citing its assertion of the dispute rule: Although EPA believes that Section 17 clearly is Indian country, we have also cited a second basis for EPA permitting HRI’s proposed project on Section 17 under the federal SDWA&emdash;EPA’s retained authority to issue permits on disputed lands. Our decision to treat the status of Section 17 as in dispute does not require NMED to concede jurisdiction, nor does it grant the Navajo Nation jurisdiction. Rather, EPA has determined only that there is a dispute such that EPA will issue the permit until the status of Section 17 is resolved. (I R. Tab 48 at 2.) This language certainly suggests that EPA Region 9, in its July 1997 letter, reconsidered or revisited the earlier Region 6 decision to treat Section 17 as Indian country, and issued a new decision to treat it as “in dispute.” Yet absent clear exercise of reconsideration authority, we look as well to the events and correspondence in the several years preceding the July 1997 letter to determine whether it represents a distinct and renewable final agency action. While NMED argues that the relevant final action of which it seeks review, with respect to both properties at issue, is EPA’s action of stating in its July 14, 1997, letter that HRI -must apply for a federal UIC permit for both sections 8 and 17, this does not entirely resolve the issue. The July 1997 letter may constitute the relevant determination for purposes of timeliness, but only if we can conclude it represents new and separate decision, or a modification EPA’s prior decision, and not a mere reassertion of, or refusal to reconsider, a prior decision. For the reasons set forth below, we conclude that it does constitute a new and separate decision triggering a new limitations period for petitioners to seek judicial review. In ICC, 482 U.S. at 278,107 S.Ct. 2360, the Supreme Court, considering the reviewability of a decision by the ICC not to reopen a proceeding under its reconsideration authority pursuant to 49 U.S.C. § 10327(g), held that “[w]hen the Commission reopens a proceeding for any reason and, after reconsideration, issues a new and final order setting forth the rights and obligations of the parties, that order — even if it merely reaffirms the rights and obligations set forth in the original order — is reviewable on its merits.” The Court directed that when an ICC decision is formally characterized as one denying reconsideration, reviewing courts should not look beyond that formal characterization to determine whether reconsideration in fact occurred. See id. at 280, 107 S.Ct. 2360. The situation here, however, does not involve EPA’s decision to exercise or refuse to exercise an explicit statutory authority to reconsider a decision as was the case in ICC. Therefore, lacking such a formal designation — reconsideration or denial of reconsideration — we must look to the substance of EPA’s action to determine whether it represents a new decision or merely a reaffirmance of previous action. Doing so, we conclude that EPA Region 9’s July 14, 1997, letter examining the merits of the jurisdictional dispute over Section 17 (and Section 8) and asserting application of the dispute rule, represents a new and separate final decision on the jurisdictional status of Section 17. If EPA had simply reasserted its original position, as it did at various points in three years of correspondence with NMED, it would not have reopened its decision. EPA’s detailed examination of the issue in its July 1997 letter and its affirmative assertion of the application of the dispute rule reflect a sufficient degree of separateness, novelty, and finality, to trigger the limitations period for judicial review. Cf. ICC, 482 U.S. at 278, 107 S.Ct. 2360; Sendra Corp. v. Magaw, 111 F.3d 162, 167 (D.C.Cir.1997) (“If for any reason the agency reopens a matter and, after reconsideration, issues a new and final order, that order is renewable on its merits, even though the agency merely reaffirms its original decision.... The new order is, in other words, final agency action and as such, a new right of action accrues and starts the running of a new limitations period for judicial review”) (citations omitted). EPA’s reconsideration of its position on Section 17 and its articulation of alternative grounds for federal UIC implementation — namely, application of its dispute rule — are more than merely a reassertion of an earlier position. Rather, the reconsideration and articulation of alternative grounds constitute a new and distinct decision on the Section 17 issue and present sufficiently final agency action to permit judicial review pursuant to 42 U.S.C. § 300j-7(a). An assertion that the agency simply “believes” Section 17 is Indian country would appear to represent a retreat from an actual determination of its statüs. This conclusion is bolstered by the agency’s specific statement of what it is determining: “only that there is a dispute such that EPA will issue the permit until the status of Section 17 is resolved.” (I R. Tab 48 at 2.) The conclusion that EPA’s July 14, 1997, letter is a distinct final action for purposes of triggering the limitations period for judicial review is bolstered by examination of the correspondence between the parties following EPA Region 6’s August 24, 1995, denial of temporary aquifer designation status for Section 17. As previously noted, that letter instructed HRI to apply to EPA Region 9, with responsibility for the Navajo Nation federal UIC program, for an aquifer exemption and discharge permit. Instead of HRI applying for a federal permit, NMED engaged in a lengthy exchange with EPA Region 9 and the Navajo Nation regarding a potential “joint permitting” arrangement. Throughout that process, NMED continued to assert Section 17 was not Indian country. Yet it is unclear to what extent Region 9 and NMED considered there to be an ongoing dispute regarding Section 17’s Indian country* status that was awaiting determination or redetermination. In correspondence from Region 9 to NMED dated March 20, 1996, Region 9 appears to assume it was proceeding under Region 6’s earlier determinations that Section 17 was Indian country. By contrast, a joint letter to HRI, sent by EPA Region 9 to NMED on June 21, 1996, but apparently never approved by NMED, proposed to admit that the parties had been “unable to resolve [their] dispute over whether EPA or NMED has permitting authority over Section 17 under the [SDWA],” to acknowledge “the potential for litigation at the end of the permitting process,” and to express “confidence]” that “[r]egardless of the ongoing legal dispute,” a resolution could be reached. (I R. Tab 37 at 3.) The likelihood of inter-agency cooperation decreased in late 1996 and early 1997. On February 11, 1997, Region 9 Administrator Felicia Marcus noted in a letter to NMED: In the last three years both EPA and NMED have held firm to our positions that each of us has exclusive authority under the [SDWA] to permit HRI’s activities on Section 17. Unfortunately, we have made no real progress towards any cooperative permitting process that would enable us to overcome the jurisdictional dispute, and I am pessimistic about any future success along those lines, given the Navajo Nation’s firm opposition to joint permitting and other problems.... Our inability to resolve the jurisdictional issue appears to be impacting HRI. (I R. Tab 44 at 1-2). Marcus then went on to propose EPA take jurisdiction over Section 17 based on the dispute rule. This resolution would “enable HRI to submit a permit application to EPA without having to wait for a legal resolution of the jurisdictional dispute.” (Id. at 2.) After NMED responded by setting forth specific statutes, regulations, and case law that it maintained supported its position, Region 9 issued its July 14, 1997, letter and an accompanying “Analysis” rejecting NMED’s positions and stating unambiguously that EPA was assuming jurisdiction over both Sections 8 and 17 under the dispute rule. When considered collectively, this correspondence indicates that Region 9 reconsidered or reexamined Region 6’s Indian country determination as to Section 17. The correspondence reflects Region 9 considered there to be an ongoing dispute that could be resolved notwithstanding Region 6’s prior determinations. Significantly, both NMED and HRI expressly considered that litigation of Region 9’s decision was possible, perhaps even likely. EPA reasons that, because it never wavered from Region 6’s initial determination that Section 17 was Indian country, the July 1997 letter and analysis cannot give rise to an independently reviewable determination. In its July 1997 letter and accompanying analysis, however, Region 9 did not merely reiterate what Region 6 had previously stated; nor did it issue a cursory reaffirmance or summary of Region 6’s prior position; it examined for the first time the legal precedent offered by NMED and HRI, analyzed that precedent in light of the particular factual scenario at hand, and reasoned from its understanding of the facts and law that Section 17 was Indian country. A large portion of Region 9’s July 1997 Analysis was devoted to discussing and distinguishing Yazzie, 909 F.2d 1387, and Watchman, 52 F.3d 1531, neither of which EPA had addressed before, and the latter of which arose after Region 6’s initial 1993 TAD decision. In short, Region 9’s July 14, 1997, determination marked the only time EPA forthrightly examined all interested parties’ competing positions and issued an opinion analyzing the issue in significant depth. It was the culmination of what can be characterized either as Region 9’s independent determination regarding the Indian country status of Section 17, or as Region 9’s reexamination of Section 17’s status (as determined by Region 6) at NMED’s request. Because NMED petitioned for judicial review within 45 days of Region 9’s July 14, 1997, letter and Analysis, this court has jurisdiction to review EPA’s determination that Section 17 is Indian country. Ill Now that we have established our jurisdiction to review these agency determinations, we ask did EPA’s actions violate the SDWA or EPA regulations. We conclude they did not. Under the APA, a court can set aside informal agency decisions, such as those before us, if the decisions were “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with the law.” 5 U.S.C. § 706(2)(A). We owe some degree of deference, under certain circumstances, to an agency’s interpretation of its governing statutes and regulations. See Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837, 842-43, 104 S.Ct. 2778, 81 L.Ed.2d 694 (1984). While petitioners argue that EPA’s determinations with respect to issues of Indian jurisdiction are entitled to no deference because they are matters outside the agency’s expertise, such an argument cannot successfully extend to the agency’s interpretation of its own procedural requirements. Interpretation of the procedural regulations pertaining to the grant, modification, and withdrawal of primacy and to the grant, denial, or revocation of aquifer exemptions are matters within the agency’s expertise, and entitled to deference under Chevron, 467 U.S. at 842-43, 104 S.Ct. 2778. Chevron requires that we ask “whether the agency’s answer is based on a permissible construction of the statute” when Congress has not “directly spoken to the precise question at issue.” Id. Because Congress has delegated authority to EPA to implement the SDWA, see 42 U.S.C. §§ 300f, 300g-1, we apply Chevron deference to the agency’s construction of those procedural requirements of its implementation left unspecified by Congress. • In addition to this deference to an agency’s construction of statutes, we also owe deference to its construction of its own regulations. “[Provided an agency’s interpretation of its own regulations does not violate the Constitution or a federal statute, it must be given ‘controlling weight unless it is plainly erroneous or inconsistent with the regulation.’ ” Stinson v. United States, 508 U.S. 36, 45, 113 S.Ct. 1913, 123 L.Ed.2d 598 (1993) (quoting Bowles v. Seminole Rock & Sand Co., 325 U.S. 410, 414, 65 S.Ct. 1215, 89 L.Ed. 1700 (1945)). If EPA’s action represents a direct violation of statutory terms that are not ambiguous, the action is of course “not in accordance with the law” and entitled to no deference. See Chevron, 467 U.S. at 842-43, 104 S.Ct. 2778; Mission Group Kansas v. Riley, 146 F.3d 775, 780 (10th Cir.1998). A. Section 8 HRI argues that EPA’s assertion of federal UIC jurisdiction over Section 8 directly violates the SDWA’s provision: “[U]ntil an Indian Tribe assumes primary enforcement responsibility, the currently applicable underground injection control program shall continue to apply.” 42 U.S.C. § 300h-1(e). Because EPA recognized New Mexico’s jurisdiction over Section 8 by granting the 1989 aquifer exemption, petitioners argue, New Mexico’s is the “currently applicable” UIC program, and thus should continue to apply until a tribe assumes primary responsibility. Such an analysis mischaracterizes the scope of EPA’s authority under the SDWA. EPA does not have the power to change the Indian country status of land— that is a status conferred by Congress. If Section 8 is indeed Indian country, then New Mexico’s program could not extend to it in the first instance and cannot be “currently applicable” within the meaning of the statute. An aquifer exemption by EPA cannot change the congressionally-defined jurisdictional status of the land. If the land in question is Indian country, the “currently applicable” program must necessarily be governed by the federal Indian lands UIC regulations, 40 C.F.R. Pt.. 147, subpart HHH. See 40 C.F.R. § 147.3000(a) (“The UIC program for the Indian lands of the Navajo ... in New Mexico is administered by EPA”). Accordingly, we reject this argument as a basis for reversal of EPA’s decision requiring HRI to seek a federal SDWA permit for Section 8. 42 U.S.C. § 300h-1(b)(3) provides that after approval of a state UIC program, “the State shall have primary enforcement responsibility for underground water sources until such time as the Administrator determines, by rule, that such State no longer meets the requirements of clause (i) or (ii) of paragraph (1)(A) of this subsection.” HRI contends that the 1989 approval of a program amendment to include the Section 8 aquifer exemption determined conclusively that Section 8 is under New Mexico primacy, and therefore EPA cannot unilaterally amend or withdraw that primacy determination without making a determination of noncompliance pursuant to 42 U.S.C. § 300h-1(b)(3). We disagree that 42 U.S.C. § 300h-1(b)(3) controls. A more reasonable reading of subsection (b)(3), viewed in the context of the entire SDWA scheme of delegated regulation and enforcement, limits its application to those instances in which EPA disapproves an entire previously approved state UIC program or substantive elements thereof. EPA’s decision at issue does not revoke New Mexico’s “primary enforcement responsibility for underground water sources” as contemplated by 42 U.S.C. § 300h-1(b)(3). Rather, it simply determines that certain lands are outside the reach of New Mexico’s program as previously approved by 40 C.F.R. § 147.1601, pursuant to 42 U.S.C. § 300h-1(b). Review of the regulations implementing the SDWA helps to elucidate the appropriate circumstances for application of the procedures required by 42 U.S.C. § 300h-1(b)(3). 40 C.F.R. § 145.34 proeedurally provides for when a state, either on its own initiative, see § 145.34(a), or on the initiative of EPA Administrator, see § 145.34(b), is relieved of its responsibilities under the SDWA. For such a substantial transfer of enforcement authority, § 145.34 understandably requires extensive notice and hearing requirements, particularly so in the case of an involuntary withdrawal, in which case the State is afforded the opportunity to remedy instances of noncompliance. See § 145.34(b)(1). The rulemaking requirements of 42 U.S.C. § 300h-1(b)(3) are directed at regulating the significant act of finding a state program substantively defective, with its accompanying requirements of opportunity to cure defects and provision for orderly transfer. Although it seems apparent that the precise circumstances of this case were not explicitly contemplated by Congress in enacting the SDWA or by the agency in promulgating the procedural regulations thereunder, our consideration of the purpose and particular requirements of 40 C.F.R. §§ 145.32 and 145.34, persuades us that the regulations pertaining to program revision, see 40 C.F.R. § 145.32, are more appropriately applicable to the action before us for review. We do not accept the “tail wags the dog” argument that a relatively small jurisdictional reassessment of certain geographic areas amounts to a determination that a state’s UIC program no longer meets SDWA requirements, invoking the procedures established by 42 U.S.C. § 300h-1(b)(3) and 40 C.F.R. § 145.34(b). Instead of constituting a withdrawal of a state program, see 40 C.F.R. § 145.34, EPA’s assertion of permitting jurisdiction over Sections 8 and 17 is better characterized as a state program revision appropriately controlled by the procedures set forth in 40 C.F.R. § 145.32(b)(4). See WNRC, 793 F.2d at 199 (“under the agency’s regulations, nonsubstantial program revisions need not be accomplished through formal rulemaking”). Therefore,' EPA’s action did not violate 42 U.S.C. § 300h-1. 40 C.F.R. § 145.32 allows for “program revision[s],” at the initiative of either the approved State or EPA. See § 145.32(a) (“Either EPA or the approved State may initiate program revision”). Given our conclusion that EPA’s action is not contrary to statute, and that the agency regulatory procedures for program revision are a proper exercise of delegated authority under the statute, we analyze EPA’s interpretation of its regulations under the Chevron framework. See Mission Group Kansas, 146 F.3d at 780-81. Under that standard, we conclude that EPA reasonably asserted jurisdiction as an EPA-initiated program revision pursuant to 40 C.F.R. § 145.32(a). The propriety of this revision turns on whether it is a “substantial” revision, requiring adherence to the particular notice and comment requirements of 40 C.F.R. § 145.32(b)(2) — requirements that even EPA does not contend were met. Section 145.32 provides that “[w]henever EPA determines that the proposed program revision is substantial, EPA shall issue public notice and provide an opportunity to comment for a period of at least 30 days.” 40 C.F.R. § 145.32(b)(2). The regulation further requires that “[n]otiee of approval of any substantial revision shall be published in the FEDERAL REGISTER. Notice of approval of non-substantial program revisions may be given by a letter from the Administrator to the State Governor or his designee.” 40 C.F.R. § 145.32(b)(4). The tentative revocation of the Section 8 aquifer exemption, affecting some 160 acres, is reasonably construed as a “nonsubstantial program revision.” WNRC, 793 F.2d at 199. Therefore, we find no procedural violation in the EPA’s assertion of jurisdiction. B. Section 17 As for Section 17, we similarly conclude that because EPA’s denial of an aquifer exemption and assertion of federal jurisdiction under the dispute rule does not represent a program withdrawal, it does not implicate the procedural requirements of 40 C.F.R. § 145.32. EPA’s initial action as to Section 17 represented a disapproval of a request for an additional aquifer exemption under 40 C.F.R. § 144.7(b)(3), which provides only that such disapproval “shall state the reasons and shall constitute final Agency action for purposes of judicial review.” ■ EPA’s initial letter of disapproval states the jurisdictional grounds for that action, and thereby satisfies the procedural requirements of § 144.7(b)(3). Likewise, its July 1997 letter states in considerable detail the reasons for its assertion of jurisdiction under the dispute rule and substantive federal Indian law. As we noted with respect to Section 8, assertion of federal jurisdiction over an area of land encompassing some 200 acres is reasonably construed as a nonsubstantial program revision for purposes of 40 C.F.R. § 145.32(b)(4), and we find no violation of procedural law or regulation. Whether EPA’s substantive decision regarding Section 17 represents an abuse of discretion or decision contrary to law is a question we confront below. IV We now consider whether EPA’s decision to assert SDWA jurisdiction over Sections 8 and 17 constitutes an action contrary to law or an abuse of discretion by EPA in light of the state adjudications discussed in Section I.C, supra, and prior EPA actions. Petitioners claim that EPA, by subjecting Sections 8 and 17 to the direct federal implementation UIC program, violated the terms of the preamble to its Indian lands UIC regulations because that land was “later adjudged” to be non-Indian land. 53 F.R. 43,096, 43,-097. Petitioners additionally argue that the collateral estoppel effects of the previous state adjudications foreclose the Navajo Nation from asserting that the lands in question are Indian country. Although EPA, which was not party to these adjudications, is not directly bound under the law of collateral estoppel, petitioners assert that EPA is obligated to regard these adjudications as binding under the “later adjudged” language of its dispute rule and thus required to remove the lands from the federal UIC program. 53 Fed.Reg. at 43,097. Because EPA was not a party to those adjudications, and because EPA, as an agency of the federal government, has an independent duty to protect Indian interests, we conclude that the agency did not err in finding, despite the state adjudications, a legitimate dispute as to the jurisdictional status of the lands in question. The federal government bears a special trust obligation to protect the interests of Indian tribes, including protecting tribal property and jurisdiction. See, e.g., Oneida County v. Oneida Indian Nation, 470 U.S. 226, 247, 105 S.Ct. 1245, 84 L.Ed.2d 169 (1985) (holding that “[t]he canons of construction applicable in Indian law are rooted in the unique trust relationship between the United States and the Indians”); Morton v. Mancan, 417 U.S. 535, 555, 94 S.Ct. 2474, 41 L.Ed.2d 290 (1974) (recognizing “ ‘Congress’ unique obligation toward the Indians”); United States v. Creek Nation, 295 U.S. 103, 109-10, 55 S.Ct. 681, 79 L.Ed. 1331 (1935) (holding that the federal executive is held to a strict fiduciary standard in relations with Indian tribes and is to take “all appropriate measures for protecting and advancing” those tribes’ interests). Felix Cohen’s Handbook summarizes the impact of this relationship on agency action: [T]he federal trust responsibility imposes strict fiduciary standards on the conduct of executive agencies — unless, of course, Congress has expressly authorized a deviation from these standards in exercise of its “plenary” .power. Since the trust obligations are binding on the United States, these standards of conduct would seem to govern all executive departments that may deal with Indians, not just those such as the Bureau of Indian Affairs which have special statutory responsibilities for Indian affairs. Moreover, in some contexts the fiduciary obligations of the United States mandate that special regard be given to the procedural rights of Indians by federal administrative agencies. Felix S. Cohen, Handbook of Federal Indian Law at 225 (footnotes omitted) (1982 ed.); see also Montana v. Blackfeet Tribe, 471 U.S. 759, 766, 105 S.Ct. 2399, 85 L.Ed.2d 753 (1985) (discussing canon of statutory construction, derived from the trust relationship, requiring construction of statutes liberally in favor of Indians and resolution of ambiguities in their favor). The trust relationship and its application to all federal agencies that may deal with Indians necessarily requires the application of a similar canon of construction to the interpretation of federal regulations. Additional Supreme Court cases emphasize a particular federal duty to safeguard Indian interests in land. See Drummond v. United States, 324 U.S. 316, 318, 65 S.Ct. 659, 89 L.Ed. 969 (1945) (holding that suits by the United States to protect Indian land interests are not barred by prior adjudications against individual Indians); United States v. Candelaria, 271 U.S. 432, 444, 46 S.Ct. 561, 70 L.Ed. 1023 (1926) (same). Considering this duty, and the broad definition of Indian country in both 18 U.S.C. § 1151 and the SDWA regulations, as well as the complicated jurisdictional history of many Indian lands, we conclude that it is reasonable for EPA to adopt an interpretation of its regulations requiring, when lands are in dispute, presumptions in favor of Indian country status and resulting federal jurisdiction. Moreover, considering the trust duty, we hold it is permissible for EPA— at least under circumstances such as these, involving adjudications ultimately resolved not on the merits but on procedural grounds, and impheating pure issues of federal Indian law — to decline to consider as “adjudged” lands as to which the agency was not a party to the relevant proceedings. The fundamental constitutional principles supporting independent federal inquiry into the title status of Indian land apply with even greater force to disputes over Indian country jurisdictional status. Jurisdictional status of land implicates not only ownership, but also the core sovereignty interests of Indian tribes and the federal government in exercising civil and criminal authority over tribal territory. EPA’s assumption that the land was not Indian country, when it previously granted an aquifer exemption for Section 8, can neither change the congressionally-determined status of that land, nor deprive the federal government of its duty and prerogative to protect Navajo governance of Indian lands. In considering the Indian country status of certain Creek nation lands in Oklahoma, we stated: “[T]he past failure to challenge Oklahoma’s jurisdiction over Creek Nation lands, or to treat them as reservation lands, does not divest the federal government of its exclusive authority over relations with the Creek nation or negate Congress’s intent to protect Creek tribal lands and Creek governance with respect to those lands.” Indian Country U.S.A., Inc. v. Oklahoma, 829 F.2d 967, 974 (10th Cir.1987) (citing United States v. John, 437 U.S. 634, 652-53, 98 S.Ct. 2541, 57 L.Ed.2d 489 (1978)). Congress’s intent to protect tribal lands and governance extends no less to EPA than to other departments of the federal government, and therefore, in accordance with Indian Country, U.S.A., the agency’s interpretation of its rule to permit recognition of a dispute under the circumstances of this case is clearly permissible. Our recent decision in Osage Tribal Council v. Department of Labor, 187 F.3d 1174 (10th Cir.1999), is not to the contrary. In Osage Tribal Council, 187 F.3d at 1183-84, we rejected an argument that the Secretary of Labor violated his trust responsibility to the Osage Tribe by initiating a proceeding under the employee protection provisions of the SDWA. The facts of that case involved the termination of an environmental inspector employed by the Tribal Council to monitor its compliance with SDWA provisions. See id. at 1178. When the inspector was terminated, allegedly for filing environmental violation reports protected under the SDWA, the Secretary brought a proceeding under 42 U.S.C. § 300j-9(i), and an Administrative Law Judge found in favor of the inspector. See id. The Tribal Council appealed, alleging in part that “in bringing [the] action, the Secretary of Labor ... violated the federal government’s trust responsibility toward the tribe.” Id. at 1183 (citing Creek Nation, 295 U.S. at 109, 55 S.Ct. 681; Cohen, supra, at 226). We restated the trust doctrine, but concluded that the Tribal Council had not demonstrated a breach of the Secretary’s “strict fiduciary standards when charged with administering Indian lands or funds” because “rather the Secretary was carrying out his duties with respect to Congress’ mandate on safe drinking water.” Id. at 1183-84 (citations omitted). In Osage Tribal Council, the Secretary of Labor was in no way administering Indian lands. In this case, by contrast, EPA’s decision, while made within the framework of administering the SDWA, implicates the core federal trust responsibilities of administering — and safeguarding — Indian lands. While there is no allegation before us of a breach of a specific statutory, treaty, or trust obligation, we nevertheless reaffirm that the federal executive is to consider its strict fiduciary obligation when interpreting regulations that directly affect its “administfration of] Indian lands.” Id. at 1183 (citing Morton v. Ruiz, 415 U.S. 199, 236, 94 S.Ct. 1055, 39 L.Ed.2d 270 (1974); Seminole Nation v. United States, 316 U.S. 286, 296, 62 S.Ct. 1049, 86 L.Ed. 1480 (1942)). The trust duty is not relevant to the decision at issue in Osage Tribal Council: whether or not to enforce the employee protection provisions of the SDWA against a tribe pursuant to Congress’s unequivocal mandate that those provisions apply to tribes. See id. at 1180-83. It is most relevant, however, when an agency decision necessarily incorporates a determination as to whether certain lands are within the scope of tribal territorial sovereignty. See, e.g., United States v. Santa Fe Pac. R.R. Co., 314 U.S. 339, 353-54, 62 S.Ct. 248, 86 L.Ed. 260 (1941) (applying principle of “solicitude of the Federal government” for Indian welfare and principle of resolving ambiguities in favor of Indians to question of tribal jurisdiction over land). Thus, this case is entirely unlike the decision in Osage Tribal Council, which implicated a clear congressional mandate regarding enforcement of SDWA whistleblower provisions against Indian Tribes, but did not implicate decisions defining the extent of Indian territorial sovereignty. The fact that the trust doctrine does not bar whistleblower suits against a tribe that happen to arise under the SDWA, see Osage Tribal Council, 187 F.3d at 1183-84, does not create a per se prohibition against application of the doctrine to government agencies whenever the SDWA happens to be involved, and certainly not when tribal lands and tribal territorial sovereignty are directly involved. Also unlike Osage Tribal Council, this case does not reflect an assertion of an affirmative cause of action based on -an official’s alleged violation of a trust duty. Rather, that duty and its accompanying canon of construction simply provide additional support for EPA’s interpretation of its regulation: That the agency, in the course of SDWA adjudication, may make an independent evaluation, based on federal law, of the Indian country status of disputed lands. The fact that EPA is not specifically charged with administration of Indian lands or funds does not render unreasonable its solicitude for core Indian interests. Our conclusion that there is no right of action under the trust duty to contest the Secretary of Labor’s enforcement of a clear congressional mandate to apply a statutory rule to Indian tribes, see id., does not obviate application of the canon of construing ambiguities to favor Indian interests to executive officials when their actions necessarily implicate determinations of the extent of tribal sovereignty. Petitioners argument — that EPA’s rejection of the Navajo Nation’s TAS application as to private fee lands in the Eastern Navajo Agency forecloses EPA’s assertion that a dispute exists as to jurisdiction over Section 8 — is without merit. EPA’s September 20, 1994, partial approval of the Navajo Nation’s TAS application states that “the Navajo nation has not satisfied the third criterion ... under section 1451 of the SDWA for federal land and tribal fee lands (except for the lands in these categories that have already been determined to be part of ‘Indian country’), private fee lands, and New Mexico state trust lands within the Eastern Navajo Agency.” (VI R. Tab 112 at 25). EPA explicitly declined to find that the Navajo Nation has no jurisdiction over federal lands, some tribal fee lands, private fee lands, and New Mexico state trust lands: It is important to note what determination EPA is and is not making in this case at this time. For those categories of lands for which EPA cannot determine whether the Navajo Nation has jurisdiction, EPA is simply stating that the Navajo Nation has not adequately shown that it does have jurisdiction. However, EPA is not determining that the Navajo Nation does not have jurisdiction. Neither is EPA determining whether or not such lands are “Indian lands” for the purposes of EPA’s UIC program in New Mexico. Id. at 20. By its own terms, EPA’s 1994 TAS decision took no position on the “Indian lands” status of such lands, and therefore its decisions later with respect to Sections 8 and 17 cannot be characterized as impermissible collateral attacks on its 1994 TAS decision. For these reasons, we decide that EPA is not foreclosed by the state adjudications or by its earlier actions in the TAS proceeding from finding a legitimate dispute as to the Indian country status of the lands at issue, and therefore EPA did not violate the terms of its dispute rule, either in declining to remove Section 17 from the federal UIC program or in placing Section 8 into that program as disputed Indian country. V EPA regulations define “Indian lands” for the purpose of the SDWA as “ ‘Indian country’ as defined in 18 U.S.C. 1151.” 40 C.F.R. § 144.3. 18 U.S.C. § 1151 defines Indian country as: (a) all land within the limits of any Indian reservation under the jurisdiction of the United States Government, notwithstanding the issuance of any patent, and including rights-of-way running through the reservation, (b) all dependent Indian communities within the borders of the United States whether within the original or subsequently acquired territory thereof, and whether within or without the limits of a state, and (c) all Indi